Dallas County's Aerial Spraying for West Nile not as Deadly to Mosquitoes as First Claimed

Don't scramble the county air force just yet. We need to do some serious reading and talking before the Dallas County does a repeat of last year's aerial spraying for West Nile disease.

I have a copy of the final Centers for Disease Control and Prevention report on last year's spraying. Sorry, can't say how I got it. Bases to cover, you know.

Maybe you remember the CDC's initial report at the end of last August claiming that the pesticide bombing of large portions of the county had reduced the population of bad mosquitoes by 93 percent. Well, they've taken a closer look.

The bad mosquito population did not go down by 93 percent after the spraying. It went up.

The CDC now reports "small but statistically significant increases in mosquito abundance" in one of three aerial spray areas. In the other two, according to the new report, there was "a similar small increase in mosquito abundance, but the difference was not significant."

Well, that depends on what you call significant. A non-scientist whose house got sprayed, I would call any increase at all pretty damned significant after you told me last year that the spraying caused a 93 percent decrease.

The report does find a positive effect on human infection rates. It says aerial spraying had "a measurable impact" on infection rates for the more serious "neuroinvasive" form of the disease -- the kind that paralyzes people.

When I read this report, the differences between infection rates in sprayed areas and nonsprayed area seems modest; the report doesn't seem to do a good job of sorting out the effect ground spraying may have had; and it hedges on all of it by calling for more research.

Then again -- and allow me to say this loud and clear -- I am not the right guy to read this report and draw grand conclusions on its finer points. This week I will be talking to people who actually do know that they're talking about for my column in next week's newspaper.

If and when your elected officials allow you to see it, you read it. See if you can make head or tails.

But before I sign off, I do want to remind us of what I think is the overarching point in terms of what we little people here on the ground were told last year. Right after the spraying was done, when the commercial spray company and the county officials who paid them were all over the news, the claim was a 93 percent kill rate.

Now that we have a more serious study, the debate needs to be whether aerial spraying is actually somehow helping the little devils multiply.